Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitation \(\gamma\) rays

• Published in: arXiv.org 2014-11
• Main Authors: Abe, K, Aihara, H, Assylbekov, S, Bay, F, Bojechko, C, Boyd, S B, Buchanan, N, Calland, R G, Cartwright, S L, Christodoulou, G, Clifton, A, Cremonesi, L, Dabrowska, A, Danko, I, Das, R, Davis, S, de Perio, P, Duboyski, T, Dumarchez, J, Dziewiecki, M, Ereditato, A, Fiorentini Aguirre, G A, Fujii, Y, Furmanski, A P, Gilje, K, Gomez-Cadenas, J J, Gonin, M, Gudin, D, Haegel, L, Haigh, M D, Hamilton, P, Hartz, M, Hignight, J, Hillairet, A, Holeczek, J, Huang, K, Ichikawa, A K, Imber, J, Ives, S J, Iwai, E, Iyogi, K, Izmaylov, A, Jo, J H, Kabirnezhad, M, Kaboth, A C, Kanazawa, Y, Karpikov, I, Katori, T, Kielczewska, D, King, S, Kitching, P, Koch, L, Koseki, K, Kropp, W, Kudenko, Y, Lee, K P, Ludovici, L, Macaire, M, Malek, M, Maruyama, T, McGrew, C, Mefodiev, A, Miller, C A, Miura, M, Nakayoshi, K, Naples, D, Nirkko, M, Nishimura, Y, Oryszczak, W, Oser, S M, Oyama, Y, Paolone, V, Petrov, Y, Pinzon Guerra, E S, Pistillo, C, Poutissou, R, Quilain, B, Rondio, E, Ruterbories, D, Scantamburlo, E, Scott, M, Shustrov, Y, Sobczyk, J T, Sobel, H, Southwell, L, Suda, Y, Suzuki, S Y, Suzuki, Y, Tacik, R, Takahashi, S, Takeda, A, Terhorst, D, Thorley, A, Toki, W, Weber, A, Wilkes, R J, Wilson, J R, M Yu, Zalewska, A, Zambelli, L
• Format: Article
• Language: English
• Subjects: Apexes; Background radiation; Cerenkov counters; Confidence intervals; Experiments; Natural radioactivity; Neutrinos; Nuclear cross sections; Oxygen; Particle physics; Windows (computer programs)
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1403.3140

We report the first measurement of the neutrino-oxygen neutral-current quasielastic (NCQE) cross section. It is obtained by observing nuclear deexcitation \(\gamma\)-rays which follow neutrino-oxygen interactions at the Super-Kamiokande water Cherenkov detector. We use T2K data corresponding to \(3.01 \times 10^{20}\) protons on target. By selecting only events during the T2K beam window and with well-reconstructed vertices in the fiducial volume, the large background rate from natural radioactivity is dramatically reduced. We observe 43 events in the \(4-30\) MeV reconstructed energy window, compared with an expectation of 51.0, which includes an estimated 16.2 background events. The background is primarily nonquasielastic neutral-current interactions and has only 1.2 events from natural radioactivity. The flux-averaged NCQE cross section we measure is \(1.55 \times 10^{-38}\) cm\(^2\) with a 68\% confidence interval of \((1.22, 2.20) \times 10^{-38}\) cm\(^2\) at a median neutrino energy of 630 MeV, compared with the theoretical prediction of \(2.01 \times 10^{-38}\) cm\(^2\).